“Maximum Purification” — Zephyr 750 Café Racer

Zephyr Café Racer from Tumulte… 

Introduced in 1990, the Kawasaki Zephyr 750 was part of a 90s resurgence of air-cooled, twin-shock, retro-style standards with roots in the Universal Japanese Motorcycles of the 70s. In 1992, a circle of Cycle World writers came to a rare consensus about what size streetbike they would own if they could have only one: 750cc.

“A great many riders find 750s ideal because this engine size-three-quarters of a liter, 45 cubic inches—represents an ideal compromise between the intense, sporty lightness of the best 600s and the big-time, pavement-ripping energy delivered by the powerful but heavy and sometimes intimidating liter-class bikes.” –CW

So the next question came as no surprise: What’s the ultimate 750? The Zephyr 750 might not astound anyone on paper, featuring a traditional cradle tube frame, air-cooled 71-hp DOHC eight-valve inline-four, and a dry weight of 443 pounds. However, the Cycle World boys kept coming back to the Zephyr as the best standard 750 streetbike available.

“Kawasaki’s Zephyr 750 gets the nod, mainly for the most elemental of reasons: It’s a blast to ride… This is the bike to help you recapture all those sensations of motorcycling you so fondly remember.” –CW

Enter our friend Frédéric “Fred” Lagarde of French workshop Tumulte. Fred earned quite the pedigree before turning to two wheels:

“I started as a race engineer in GT cars for more than 10 years, so I have a solid experience in mechanics, welding, wiring and reliability!”

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We’ve featured several of Fred’s projects, which span the gamut of styles and donors. For this build — his 25th — the Zephyr 750 was the perfect candidate.

“The customer’s specifications were rather simple: pure café racer, clip-ons, and maximum purification (while retaining the passenger footrests and 1 ½ place saddle).”

Whereas many builders simply slap a loop onto the back of the frame, Fred rebuilt the whole subframe from the tank back:

“I redesigned all the angles from below the fuel tank to the rear end in order to have better harmony in the lines.”

A custom saddle with diamond stitching matches the pattern of the grips, while a mini lithium is housed underneath the seat. Up front there’s a Koso LED headlight and new speedometer.

As the bike had been sitting for many years, Fred overhauled the engine and outfitted it with a Delkevic stainless steel exhaust system. As a row of four air filters wouldn’t fit the frame, he designed and 3D-printed a custom intake to hold twin BMC filters — an option available for sale to other Zephyr owners.

The paint and typography are a tribute to the US Army — another customer specification. With the clip-ons and original suspension, Fred says the ride is sportier without being harsh — perfect for the roads of southwestern France:

“Now it’s ready to take on the winding roads in the Lot region around Figeac!”

Below, we talk to Fred for a few more details about the build.

Zephyr 750 Café Racer: Builder Interview

• What’s the make, model, and year of the bike?

Kawasaki Zephyr 750, 1991.

• What was the design concept and what inspired the build?

Pure café racer project for this Zephyr from the 90s, classic but still effective! The Zephyr is indeed a good base for a build, of the same caliber as the roadsters of the 90s like the Seven Fifty, XJR, and other CBs.

The customer’s specifications were rather simple: pure café racer, clip-ons, and maximum purification (retaining the passenger footrests all the same, and 1 ½ place saddle). Military green paint with the American Army star, with the use of the US army typography for a nod to the 25th release from the Tumulte workshop.

• What custom work was done?

The rear buckle is tailor-made, echoing the existing frame angles for better harmony. The wiring harness has been completely revised and incorporates new elements such as the speedometer, the mini lithium battery housed under the saddle for streamlining’s sake, and the Koso LED headlight — more discreet than the original and with more lighting. Strong!

Always with attention to detail, the saddle stitching repeats the diamond pattern of the grips.

On the mechanical side, we did a major overhaul and refurbishment, as the bike hadn’t been used for years. After this makeover, the engine was given a little makeover with the adaptation of BMC air filters and a complete Delkevic stainless steel exhaust system in order to free the beast, with perfect carburetor adjustments thanks to the temporarily installed lambda probe.

Note the in-house filter offsets to bypass the frame, available as an option for sale.

Now it’s ready to take on the winding roads in the Lot region around Figeac!

• Can you tell us what it’s like to ride the completed bike?

It’s kind of sporty with the clip-ons, but also comfortable with the original suspension. The engine is quite nice for a 30-year-old bike! With the complete exhaust and the BMC filters, the sound is pleasant but not too loud.

• Was there anything done during this build that you are particularly proud of?

Actually it’s more about the work on the frame: Usually you see café racers with just a rear subframe, but here I redesigned all the angles from below the fuel tank to the rear end in order to have better harmony in the lines.

Also the design of the filters support: Four filters couldn’t fit because of the frame, so I designed and 3D-printed these supports to have only two filters.

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Website: www.tumulte.bike
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Facebook: @tumulte.bike

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